Was re-reading Dissonance’s reply to your quote, and it made me wonder about other moral questions about wartime actions at that time. Specifically, would it have been just for the Allies to use chemical weapons in the Pacific on heavily fortified installations like Iwo Jima or parts of Okinawa? In the case of Iwo, the occupants were, IIRC, exclusively military, which was obviously not the case for Okinawa.
Would it even have been effective, especially as the Allies had not invented nerve gas at that point, so would have been limited to chlorine, phosgene, mustard, and perhaps HCN as well? Given that roughly as many lives were saved by having Iwo’s runways as were lost taking it, attacking Iwo still was a marginally good idea. But it would have been nice for the Allies to not have suffered nearly 7,000 killed and over 19,000 wounded. In his memoirs, Stanley Lovell, Director of R&D for the OSS, felt that a great opportunity had been missed to take the island with minimal casualties. The portion of the article (itself part of the History of the U.S. Marine Corps in WW II, Volume 4, Western Pacific Operations, (.pdf) at page 612) where the cite occurs, goes into some detail about the pluses and minuses of using chemicals, as well as the debate within the upper levels of the Joint Chiefs and the White House concerning their use.. The Bulletin of Atomic Scientists naturally disagrees with the idea that using chemicals (or any WMD probably, given their slant) would have been effective.
I mention Iwo because at that point, the Japanese were incapable of effectively retaliating with those weapons at that site. (Which is the real reason NBC weapons in the present day have predominantly only been used against a power that cannot retaliate with them. Though I think Iran and Iraq used them against each other during their long war, though not against each others’ cities, interestingly.) Granted, had Olympic and Coronet occurred, the Japanese would have felt free to use them on their own soil, and that would have only added to the misery for the Allies. No doubt the Allies had that in mind when deciding not to use chemicals in the Pacific.
Morally, is using chemical weapons against soldiers that much worse than firebombing entire cities?